U.S. patent application number 15/758212 was filed with the patent office on 2018-09-13 for display device, brightness defect correction method for display device, and brightness defect correction device for display device.
The applicant listed for this patent is Panasonic Liquid Crystal Display Co., Ltd.. Invention is credited to Masahiro MORI, Shigeyuki MORI, Kazuya NAKAMURA, Takao TANAKA.
Application Number | 20180261168 15/758212 |
Document ID | / |
Family ID | 58239501 |
Filed Date | 2018-09-13 |
United States Patent
Application |
20180261168 |
Kind Code |
A1 |
MORI; Masahiro ; et
al. |
September 13, 2018 |
DISPLAY DEVICE, BRIGHTNESS DEFECT CORRECTION METHOD FOR DISPLAY
DEVICE, AND BRIGHTNESS DEFECT CORRECTION DEVICE FOR DISPLAY
DEVICE
Abstract
For suppressing a deterioration of display quality due to a
luminance defect, a display device, a method of correcting a
luminance defect and a luminance defect corrector are provided. The
display device includes a first substrate (SUB1) having gate lines
(GL), data lines (DL), pixel electrodes (PIT), and a common
electrode (CIT) on a first glass substrate (GB1), and a second
substrate (SUB2) having a plurality of optically transparent parts
(CF) and a light shield part (BM) on a second glass substrate
(GB2). The first or second glass substrate (GB1) or (GB2) contains
a dimmer (10) including a plurality of dimming regions (20) that
reduce the transmission of light. The dimmer (10) is formed to be
superimposed on a trapped foreign matter (33) in plan view. This
reduces the transmission of light from the luminance defect to
suppress a deterioration of display quality.
Inventors: |
MORI; Masahiro; (Osaka,
JP) ; MORI; Shigeyuki; (Osaka, JP) ; TANAKA;
Takao; (Hyogo, JP) ; NAKAMURA; Kazuya; (Chiba,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Panasonic Liquid Crystal Display Co., Ltd. |
Hyogo |
|
JP |
|
|
Family ID: |
58239501 |
Appl. No.: |
15/758212 |
Filed: |
August 25, 2016 |
PCT Filed: |
August 25, 2016 |
PCT NO: |
PCT/JP2016/003875 |
371 Date: |
March 7, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G09G 3/006 20130101;
G02F 1/13306 20130101; G02F 1/136259 20130101; G02F 1/1309
20130101; G02F 1/133514 20130101; G09G 3/36 20130101; G02F 1/133512
20130101; G02F 1/133611 20130101; G09G 2330/10 20130101; G09G
2320/0233 20130101; G09G 2330/08 20130101; G02F 2201/508
20130101 |
International
Class: |
G09G 3/36 20060101
G09G003/36; G02F 1/1335 20060101 G02F001/1335; G02F 1/133 20060101
G02F001/133; G02F 1/1368 20060101 G02F001/1368; H01L 27/12 20060101
H01L027/12 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 11, 2015 |
JP |
2015-178999 |
Claims
1. A display device comprising a first substrate having a plurality
of signal lines and display electrodes on a first glass substrate
and a second substrate having a plurality of optically transparent
parts and light shield parts on a second glass substrate, the
display device having a luminance defect, wherein at least one of
the first glass substrate and the second glass substrate contains a
dimmer, the dimmer including a plurality of dimming regions having
a lower transmittance of light than the glass substrate containing
the dimmer, the dimmer being formed so as to be superimposed on a
foreign matter, a cause of the luminance defect, in plan view.
2. The display device according to claim 1, wherein adjacent ones
of the dimming regions have overlapping regions.
3. The display device according to claim 1, wherein the dimmer has
a projected shape that is enlarged from a shape of the foreign
matter, the cause of the luminance defect.
4. The display device according to claim 1, wherein the dimmer
includes a dimming layer where the dimming regions are arranged in
a planar fashion and the display device includes multiple dimming
layers formed in a thickness direction of the first glass substrate
or the second glass substrate containing the dimmer.
5. The display device according to claim 4, wherein the dimming
layers include a first dimming layer formed near the foreign
matter, the cause of the luminance defect, and a second dimming
layer formed remote from the foreign matter, the first dimming
layer having a smaller shape than the second dimming layer.
6. The display device according to claim 5, wherein centers of the
dimming regions making up the second dimming layer are separated
from centers of the dimming regions making up the first dimming
layer.
7. The display device according to claim 5, wherein the dimming
regions making up the first dimming layer are smaller in volume
than the dimming regions making up the second dimming layer.
8. A method of correcting a luminance defect, comprising the steps
of: testing lighting of a display panel in order to detect the
luminance defect; detecting a position and a shape of the luminance
defect; calculating a position and a shape of a formation region of
a dimmer from the detected luminance defect; and forming, in a
glass substrate, the dimmer including a plurality of dimming
regions having a lower transmittance of light than the glass
substrate, the dimmer being formed by irradiating the formation
region of the dimmer in the glass substrate with an energy
beam.
9. The method of correcting a luminance defect according to claim
8, wherein the testing to forming steps are repeated until no
luminance defect is detected.
10. The method of correcting a luminance defect according to claim
8, wherein in the forming step, the dimmer including a plurality of
dimming layers is formed, the dimming layers including a first
dimming layer and a second dimming layer with the dimming regions
arranged in a planar fashion, and the dimming regions making up the
first dimming layer are formed by a pulse laser having lower power
than the dimming regions making up the second dimming layer farther
from a cause of the luminance defect than the first dimming
layer.
11. The method of correcting a luminance defect according to claim
10, wherein the dimming regions making up the first dimming layer
are formed by a pulse layer having lower peak intensity than that
for the dimming regions making up the second dimming layer.
12. The method of correcting a luminance defect according to claim
10, wherein the dimming regions making up the first dimming layer
are formed by a pulse layer having a longer wavelength than that
for the dimming regions making up the second dimming layer.
13. A luminance defect corrector comprising: a detector that
detects a luminance defect of a display device by illuminating the
display device; an arithmetic unit that calculates a formation
region for forming a dimmer including a plurality of dimming
regions, from a position and a shape of the detected luminance
defect; an energy beam oscillator that emits an energy beam to be
used for forming the dimming regions; a slit that spatially
transmits the energy beam to a position where the dimming region is
formed; a condenser lens that converges the energy beam; and a
drive unit that moves an irradiation region of the energy beam and
the display device relative to each other.
14. The luminance defect corrector according to claim 13, wherein
the energy beam oscillator generates a pulse laser beam of 1
picosecond or less.
15. The luminance defect corrector according to claim 13, wherein
the energy beam oscillator is capable of oscillating energy beams
of multiple wavelengths and selecting a wavelength of the energy
beam emitted to form the dimming region.
16. The luminance defect corrector according to claim 13, further
comprising a beam separator that splits or divides the energy beam
having passed through the slit, into a plurality of energy beams,
wherein the split or divided energy beams are caused to converge
through the condenser lens and focuses of the energy beams are
superimposed on one another.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a display device, a method
of correcting a luminance defect, and a luminance defect
corrector.
BACKGROUND OF THE INVENTION
[0002] Display devices include, for example, a liquid crystal
display that applies an electric field generated between a pixel
electrode and a common electrode to a liquid crystal layer, which
is interposed between a pair of substrates, so as to drive a liquid
crystal. This can display an image with an adjusted amount of light
passing through a region between the pixel electrode and the common
electrode.
[0003] In the related art, for example, it is known that a liquid
crystal display has a so-called luminance defect (may be called a
pixel defect), that is, a pixel having a higher display luminance
than a desired luminance. A luminance defect is caused by, for
example, a foreign matter trapped between a pair of substrates in
the manufacturing process of a liquid crystal display. Such a
foreign matter disturbs liquid crystal orientation and causes a
short circuit between a pixel electrode and a common electrode.
[0004] A method of correcting the luminance defect is disclosed in,
for example, Japanese Patent Laid-Open No. 2009-080163.
[0005] In the method of Japanese Patent Laid-Open No. 2009-080163,
a common electrode at a peripheral portion of a foreign matter is
irradiated with a laser beam, so that the common electrode in
contact with the foreign matter is isolated from other
circuits.
[0006] Patent Document 1: Japanese Patent Laid-Open No.
2009-080163
DISCLOSURE OF THE INVENTION
[0007] In the method of Japanese Patent Laid-Open No. 2009-080163,
however, the common electrode is broken by irradiation with a laser
beam. This may disadvantageously scatter an electrode material
during breakage or cause thermal energy adversely affecting other
circuits. Thus, in the method of the related art, the display
accuracy of peripheral pixels may be reduced by breaking a
peripheral circuit particularly in recent display devices having
high resolutions. Thus, even if display quality reduced by a
luminance defect can be improved, it is difficult to maintain the
display quality in the overall display device.
[0008] The present invention has been devised in view of the
circumstances. An object of the present invention is to provide a
display device, a method of manufacturing the same, and production
equipment of the same by which a deterioration of display quality
due to a luminance defect can be suppressed while keeping display
quality in the overall display device.
[0009] In order to attain the object, a display device according to
the present invention includes a first substrate having a plurality
of signal lines and display electrodes on a first glass substrate
and a second substrate having a plurality of optically transparent
parts and light shield parts on a second glass substrate, the
display device having a luminance defect, wherein at least one of
the first glass substrate and the second glass substrate contains a
dimmer, the dimmer including a plurality of dimming regions having
a lower transmittance of light than the glass substrate containing
the dimmer, the dimmer being formed so as to be superimposed on a
foreign matter, a cause of the luminance defect, in plan view.
[0010] Moreover, adjacent ones of the dimming regions preferably
have overlapping regions.
[0011] In the display device according to the present invention,
the dimmer preferably has a projected shape that is enlarged from
the shape of the foreign matter, the cause of the luminance
defect.
[0012] Furthermore, the dimmer preferably includes at least one
dimming layer where the dimming regions are arranged in a planar
fashion, the at least one dimming layer including multiple dimming
layers formed in the thickness direction of the glass substrate
containing the dimmer.
[0013] Moreover, the dimming layers include a first dimming layer
and a second dimming layer, wherein the first dimming layer formed
near the foreign matter, the cause of the luminance defect,
preferably has a smaller shape than the second dimming layer formed
remote from the foreign matter.
[0014] Furthermore, the centers of the dimming regions making up
the second dimming layer are preferably separated from the centers
of the dimming regions making up the first dimming layer.
[0015] Moreover, the dimming regions making up the first dimming
layer are preferably smaller in volume than the dimming regions
making up the second dimming layer.
[0016] A method of correcting a luminance defect according to the
present invention, the method including the steps of: testing
lighting of a display panel in order to detect the luminance
defect; detecting the position and the shape of the luminance
defect; calculating the position and the shape of the formation
region of a dimmer from the luminance defect detected in the
detecting step; and forming the dimmer including a plurality of
dimming regions having a lower transmittance of light than the
glass substrate, the dimmer being formed by irradiating the
formation region of the dimmer on the glass substrate with an
energy beam.
[0017] Furthermore, the testing to forming steps are preferably
repeated until no luminance defect is detected.
[0018] Moreover, in the forming step, the dimmer including a
plurality of dimming layers is preferably formed, the dimming
layers including a first dimming layer and a second dimming layer
with the dimming regions arranged in a planar fashion, and the
dimming regions making up the first dimming layer are preferably
formed by a pulse laser having lower power than the dimming regions
making up the second dimming layer farther from the cause of the
luminance defect than the first dimming layer.
[0019] Furthermore, the dimming regions making up the first dimming
layer are preferably formed by a first pulse laser having lower
peak intensity than a second pulse laser forming the dimming
regions making up the second dimming layer.
[0020] Moreover, the dimming regions making up the first dimming
layer are preferably formed by a first pulse laser having a longer
wavelength than a second pulse laser forming the dimming regions
making up the second dimming layer.
[0021] A luminance defect corrector according to the present
invention includes: a detector that detects a luminance defect of a
display device by illuminating the display device; an arithmetic
unit that calculates a formation region for forming a dimmer
including a plurality of dimming regions, from the position and the
shape of the detected luminance defect; an energy beam oscillator
that emits an energy beam to be used for forming the dimming
regions; a slit that spatially transmits the energy beam to a
position where the dimming region is formed; a condenser lens that
converges the energy beam; and a drive unit that moves the
irradiation region of the energy beam and the display device
relative to each other.
[0022] In the luminance defect corrector according to the present
invention, the energy beam oscillator preferably generates a pulse
laser beam of 1 picosecond or less.
[0023] Furthermore, the energy beam oscillator is preferably
capable of oscillating energy beams of multiple wavelengths and
selecting the wavelength of the energy beam emitted to form the
dimming region.
[0024] The luminance defect corrector according to the present
invention further includes a beam separator that splits or divides
the energy beam having passed through the slit, into a plurality of
energy beams, wherein the split or divided energy beams are caused
to converge through the condenser lens and the focuses of the
energy beams are superimposed on one another.
[0025] The present invention can suppress the occurrence of a
luminance defect in the display device.
[0026] According to the present invention, the dimmer including the
dimming regions is formed in the display device, thereby
suppressing a deterioration of display quality (luminance defect).
The display quality is deteriorated because polarization disturbed
by a foreign matter trapped in the display device interferes with
control on the amount of display light of the display device (the
amount of light transmitted from a backlight).
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 shows the overall configuration of a liquid crystal
display according to an embodiment of the present embodiment;
[0028] FIG. 2 is a plan view showing the configuration of a part of
a display panel;
[0029] FIG. 3 is a cross-sectional view taken along line A1-A2 of
FIG. 2;
[0030] FIG. 4 is a cross-sectional view schematically showing an
example of a luminance defect;
[0031] FIG. 5 is a cross-sectional view showing the configuration
of a pixel having a dimmer in the liquid crystal display of the
present invention;
[0032] FIG. 6 is a cross-sectional view showing another
configuration of the pixel having the dimmer in the liquid crystal
display of the present invention;
[0033] FIG. 7 is an enlarged schematic diagram showing overlapping
dimming regions in the liquid crystal display of the present
invention;
[0034] FIG. 8 is a top view showing the configuration of the pixel
having the dimmer in the liquid crystal display of the present
invention;
[0035] FIG. 9 is an enlarged schematic diagram showing the
configuration of the dimmer in the liquid crystal display of the
present invention;
[0036] FIG. 10 is a top view showing the configuration of the pixel
having the dimmer in the liquid crystal display of the present
invention;
[0037] FIG. 11 is an enlarged schematic diagram showing the
configuration of the dimmer in the liquid crystal display of the
present invention;
[0038] FIG. 12 is an enlarged schematic diagram showing the
configuration of the dimmer in the liquid crystal display of the
present invention;
[0039] FIG. 13 is a flowchart showing a method of correcting a
luminance defect in the liquid crystal display of the present
invention;
[0040] FIG. 14 is another flowchart showing a method of correcting
a luminance defect in the liquid crystal display of the present
invention;
[0041] FIG. 15 is a schematic diagram showing the configuration of
production equipment for the liquid crystal display of the present
invention; and
[0042] FIG. 16 is a schematic diagram showing another configuration
of the production equipment for the liquid crystal display of the
present invention.
DESCRIPTION OF THE EMBODIMENT
[0043] An embodiment of the present invention will be described
below with reference to the accompanying drawings.
[0044] In the following embodiment, a liquid crystal display will
be discussed as an example. The display device of the present
invention is not limited a liquid crystal display. For example, an
organic electroluminescent display device may be used.
[0045] FIG. 1 is a plan view showing the overall configuration of a
liquid crystal display according to the present embodiment.
[0046] A liquid crystal display LCD includes a display panel DP
that displays an image, driving circuits (a data-line driving
circuit 30, a gate-line driving circuit 31) that drive the display
panel DP, a control circuit (not shown) that controls the driving
circuits, and a backlight device 37 (FIG. 3) that backlights the
display panel DP.
[0047] FIG. 2 is a plan view showing the configuration of a part of
the display panel DP. FIG. 3 is a cross-sectional view taken along
line A1-A2 of FIG. 2. FIGS. 2 and 3 show a pixel P.
[0048] The display panel DP includes a thin-film transistor
substrate SUB1 (Hereinafter will be called a TFT substrate SUB1) on
the back side of the display panel DP, a color filter substrate
SUB2 (Hereinafter, will be called a CF substrate SUB2) that is
disposed on the front side of the display panel DP so as to be
opposed to the TFT substrate SUB1, and a liquid crystal layer LC
interposed between the TFT substrate SUB1 and the CF substrate
SUB2. The TFT substrate SUB1 corresponds to a first substrate and
the CF substrate SUB2 corresponds to a second substrate.
[0049] The TFT substrate SUB1 has a plurality of data lines DL
extended in the column direction and a plurality of gate lines GL
extended in the row direction. Thin film transistors TFT are formed
near the intersections of the data lines DL and the gate lines GL.
A rectangular region surrounded by the two adjacent data lines DL
and the two adjacent gate lines GL is defined as the pixel P. The
pixels P are arranged in a matrix on the TFT substrate SUB1.
[0050] The pixel P has a pixel electrode PIT (display electrode)
that includes a translucent conductive film made of indium tin
oxide (ITO) and so on. As shown in FIG. 2, the pixel electrode PIT
has openings 32 (e.g., slits) that are shaped like strips. The thin
film transistor TFT has a semiconductor layer SEM made of amorphous
silicon (aSi) on a gate insulating film GSN (FIG. 3). A drain
electrode DM and a source electrode SM are formed on the
semiconductor layer SEM (FIG. 2). The drain electrode DM is
electrically connected to the data line DL. The source electrode SM
and the pixel electrode PIT are electrically connected to each
other via a contact hole CONT.
[0051] The laminated structure of the parts of the pixel P is not
limited to the configuration of FIG. 3. A known configuration may
be used instead. For example, in the configuration of FIG. 3, the
gate lines GL (FIG. 2) are formed on a glass substrate GB1 of the
TFT substrate SUB1 and the gate insulating film GSN is formed so as
to cover the gate lines GL. Moreover, the data lines DL are formed
on the gate insulating film GSN and an insulating film PAS is
formed so as to cover the data lines DL. Furthermore, a common
electrode CIT (display electrode) is formed on the insulating film
PAS, and an upper insulating film UPAS is formed so as to cover the
common electrode CIT. The pixel electrode PIT is formed on the
upper insulating film UPAS, and an alignment layer AF is formed so
as to cover the pixel electrode PIT. A polarizing plate POL1 (first
polarizing plate) is formed on the back side of the glass substrate
GB1.
[0052] In the CF substrate SUB2, a black matrix BM (light shield
part) and a color filter CF (e.g., a red part, a green part, and a
blue part) (optically transparent part) are formed on a glass
substrate GB2. An overcoat layer OC is formed so as to cover the
black matrix BM and the color filter CF. A polarizing plate POL2
(second polarizing plate) is formed on the front side of the glass
substrate GB2.
[0053] According to the configuration of FIG. 3, the liquid crystal
display LCD has a so-called in-plane switching (IPS) configuration.
The liquid crystal display of the present embodiment is not limited
to this configuration.
[0054] A method of driving the liquid crystal display LCD will be
simply described below.
[0055] A scanning gate voltage outputted from the gate-line driving
circuit is supplied to the gate lines GL, whereas a video data
voltage outputted from the data-line driving circuit is supplied to
the data lines DL. When a gate on voltage is supplied to the gate
line GL, the semiconductor layer SEM of the thin film transistor
TFT decreases in resistance and a data voltage supplied to the data
line DL is supplied to the pixel electrode PIT through the source
electrode SM. Moreover, a common voltage outputted from a common
electrode driving circuit (not shown) is supplied to the common
electrode CIT. Thus, an electric field (driving electric field) is
generated between the pixel electrode PIT and the common electrode
CIT and drives the liquid crystal layer LC so as to display an
image.
[0056] In this case, the liquid crystal display LCD may have a
luminance defect in the manufacturing process such that the display
luminance of a pixel is higher than a desired luminance. FIG. 4
shows an example of a luminance defect of the pixel P.
[0057] FIG. 4 shows that a foreign matter, e.g., an organic matter
or a metal is trapped between the TFT substrate SUB1 and the CF
substrate SUB2 in the manufacturing process of the liquid crystal
display LCD. In the pixel P of FIG. 4, a foreign matter (tramp
material) 33 disturbs liquid crystal orientation so as to leak
backlight 34, leading to a luminance defect.
[0058] The liquid crystal display LCD according to the present
embodiment is configured to suppress the luminance defect.
Specifically, as shown in FIG. 5, the glass substrate GB2 of the CF
substrate SUB2 contains a dimmer 10 that reduces the transmission
of the backlight 34. The dimmer 10 includes a plurality of dimming
regions 20 that are arranged at certain intervals in a planar
fashion in a part of the glass substrate GB2 according to the size
of the foreign matter 33.
[0059] The dimming regions 20 are produced by coloring on a part of
the glass substrate GB2 such that the transmittance of the
backlight 34 passing through the dimming regions 20 is lower than
that of the backlight 34 passing through the glass substrate GB2
around the dimming regions 20.
[0060] Alternatively, the dimming regions 20 are produced with a
phase change on a part of the glass substrate GB2 such that the
transmittance of the backlight 34 passing through the dimming
regions 20 is lower than that of the backlight 34 passing through
the glass substrate GB2 around the dimming region 20.
[0061] The dimming regions 20 are arranged at certain intervals in
a planar fashion. The adjacent dimming regions 20 may be in contact
with each other in a planar fashion so as to form the dimmer
10.
[0062] The dimming regions 20 can be formed by irradiating the
glass substrate GB2 with an energy beam outside the display panel
DP from the polarizing plate POL2.
[0063] FIG. 6 shows another configuration for suppressing the
luminance defect in the liquid crystal display LCD according to the
present embodiment. FIG. 7 is an enlarged schematic diagram showing
the overlapping dimming regions 20 in the liquid crystal display
according to the present embodiment.
[0064] In the dimmer 10, the dimming regions 20 arranged in a
planar fashion may have overlapping portions 38 where the adjacent
dimming regions 20 spatially overlap each other. Generally, the
dimming capability of the dimming region 20 decreases from the
center toward the outer edge. Thus, if the dimming regions 20 are
spaced from each other or are adjacent to each other, dimming
characteristics vary in the region of the dimmer 10. Hence, the
dimming characteristics of the dimmer 10 can be made uniform by, as
shown in FIG. 7, spatially overlapping portions of the adjacent
dimming regions 20 so as to superimpose the outer edges of the
dimming regions 20. The dimming region has a high transmittance and
degraded dimming characteristics on the outer edges.
[0065] FIG. 8 is a top schematic diagram of the dimmer 10 viewed
from a liquid crystal display surface. The dimmer 10 is formed so
as to be superimposed on the foreign matter 33, the cause of a
luminance defect, in plan view. The dimmer 10 may be formed along
the shape of the luminance defect of the foreign matter 33, or may
have an enlarged analogous shape of the luminance defect so as to
cover the luminance defect caused by the foreign matter 33.
[0066] Specifically, the dimmer 10 and the luminance defect of the
foreign matter 33 may be identical in form and size in plan view.
The dimmer 10 may have the same shape as the luminance defect and
cover the luminance defect, or the dimmer 10 may have an enlarged
analogous shape of the luminance defect of the foreign matter 33 in
plan view so as to cover and surround the shape of the luminance
defect.
[0067] The dimmer 10 does not need to have the same shape as the
luminance defect as long as the dimmer 10 can cover the shape of
the luminance defect in plan view.
[0068] In this case, the same shape as the luminance defect of the
foreign matter 33 in plan view is the shape of the luminance defect
of the foreign matter 33 when the foreign matter 33 is projected to
the surface of the glass substrate GB2 in a direction orthogonal to
the surface of the glass substrate GB2.
[0069] The dimmer 10 attenuates the transmitted light of the
backlight 34. For example, the dimmer 10 always blocks light even
if light is to be transmitted for a display device. As shown in
FIG. 8, the dimmer 10 is formed only in a necessary and sufficient
region according to the shape of the luminance defect. This allows
a region other than the dimmer 10 to effectively function and
prevents deactivation of an overall pixel having a luminance
defect. Since the dimmer 10 is formed only in the necessary and
sufficient region, the productivity of the dimmer 10 can be
improved.
[0070] Conversely, the dimmer 10 formed larger than the shape of
the luminance defect of the foreign matter 33 can more reliably
reduce the part of the luminance defect. If the dimmer 10 has an
analogous shape larger than the luminance defect, a magnification
only needs to be set to prevent leakage of light when the display
panel DP is viewed in a diagonal direction.
[0071] In other words, the shape and size of the dimmer 10 are more
preferably determined according to a state of the luminance
defect.
[0072] FIG. 9 is an enlarged schematic diagram showing the
configuration of the dimmer, that is, another configuration for
suppressing the luminance defect in the liquid crystal display LCD
according to the present embodiment.
[0073] The dimmer 10 includes first and second dimming layers 11
and 12 stacked in the thickness direction of the display panel DP
in the glass substrate GB2. The first and second dimming layers 11
and 12 include the dimming regions 20 arranged in a planar fashion.
The number of layers is not limited to two.
[0074] Since the dimmer is composed of multiple layers, the degree
of dimming can be controlled according to the number of layers of
the dimmer. The state of the luminance defect changes according to
the size and shape of the trapped foreign matter 33 and thus varies
the necessary dimming characteristics of the dimmer 10. The dimmer
is provided with the necessary and sufficient number of layers
according to the degree of a luminance defect, thereby improving
productivity for forming the dimmer.
[0075] FIG. 10 is a top schematic diagram showing another
configuration for suppressing the luminance defect in the liquid
crystal display LCD according to the present embodiment. The part
of a luminance defect is viewed from the liquid crystal display
surface.
[0076] If the dimmer 10 includes the first and second dimming
layers 11 and 12 stacked in the thickness direction of the display
panel DP, the dimmer 10 has an analogously enlarged shape of the
luminance defect in plan view. The magnification of the first
dimming layer 11 near the foreign matter 33 may be smaller than
that of the second dimming layer 12 remote from the foreign matter
33. In FIG. 10, the first and second dimming layers 11 and 12 are
stacked in different sizes in plan view. Since light leaking from
the foreign matter 33 radially extends, the magnification of the
second dimming layer 12 formed at a position remote from the
foreign matter 33 is increased so as to more effectively reduce the
leakage of light. The number of layers of the dimmer 10 is not
limited to two.
[0077] FIG. 11 is an enlarged schematic diagram showing the
configuration of the dimmer, that is, another configuration for
suppressing the luminance defect in the liquid crystal display LCD
according to the present embodiment.
[0078] If the dimmer 10 includes the first and second dimming
layers 11 and 12 stacked in the thickness direction of the display
panel DP, a center 35 orthogonal to the glass substrate GB2 of the
dimming region 20 making up the second dimming layer 12 may not
coincide with a center 36 orthogonal to the glass substrate GB2 of
the dimming region 20 making up the adjacent first dimming layer
11.
[0079] The transmittance of light varies between the center and the
outer edge of the dimming region 20. Thus, the center 35 of the
dimming region 20 of the second dimming layer 12 is shifted from
the center 36 of the dimming region 20 of the first dimming layer
11, thereby alternately arranging the centers and the outer edges
of the dimming regions 20 in the thickness direction of the display
panel DP. This can achieve uniform dimming characteristics over the
dimmer 10 including the stacked layers.
[0080] The center 35 of the dimming region 20 making up the second
dimming layer 12 is located at a midpoint between the centers 36 of
the two dimming regions 20 making up the first dimming layers 11,
thereby achieving the most uniform dimming characteristics. The
number of layers of the dimmer 10 is not limited to two. In the
case of three or more dimming layers, the centers of the dimming
regions making up the adjacent dimming layers may be separated from
each other.
[0081] FIG. 12 is an enlarged schematic diagram showing the
configuration of the dimmer in another configuration for
suppressing the luminance defect in the liquid crystal display LCD
according to the present embodiment.
[0082] If the dimmer includes the first and second dimming layers
11 and 12 stacked in the thickness direction of the display panel
DP, a dimming region 20B making up the second dimming layer 12
remote from the foreign matter 33 may have a larger volume than a
dimming region 20A making up the first dimming layer 11 near the
foreign matter 33. The size of the dimming region is affected by
the intensity and density of an emitted energy beam. The dimming
region is increased by irradiation with a high-intensity energy
beam. In the formation of the dimming regions, a high-energy beam
partially reaches the lower liquid crystal layer. The high-energy
beam reaching the liquid crystal layer damages the liquid crystal
layer. Thus, the dimming region 20A making up the first dimming
layer 11 near the foreign matter 33 is preferably formed by
irradiation with a low-intensity energy beam so as to reduce damage
to the liquid crystal layer LC. The number of layers of the dimmer
10 is not limited to two.
[0083] Moreover, if the first dimming layer 11 is formed near the
foreign matter 33 and the second dimming layer 12 is formed farther
from the foreign matter 33 than the first dimming layer 11, an
energy beam leaking in the formation of the dimming regions 20 is
partially absorbed by the first dimming layer 11 formed near the
luminance defect. Thus, the possibility of damage to a liquid
crystal can be reduced even if a high-intensity energy beam is
emitted, thereby improving productivity for forming the second
dimming layer 12.
[0084] The embodiments varying in configurations were described in
the foregoing explanation. The configuration corresponding to FIG.
6, the configuration corresponding to FIG. 9, and the configuration
corresponding to FIG. 12 are suitable in this order in view of
productivity and so on.
[0085] The dimmers 10 according to the embodiments may be formed in
the glass substrate GB1 of the TFT substrate SUB1. Alternatively,
the dimmer 10 may be formed in each of the glass substrate GB1 and
the glass substrate GB2. In other words, the dimmer 10 only needs
to be formed in at least one of the glass substrate GB1 of the TFT
substrate SUB1 and the glass substrate GB2 of the CF substrate
SUB2. Moreover, the dimmer in the glass substrate GB1 may be formed
at the same position as the dimmer formed in the glass substrate
GB2 or at a different position from the dimmer formed in the glass
substrate GB2. For example, the dimmer formed in the glass
substrate GB1 may be formed near the backlight in the glass
substrate GB1, whereas the dimmer formed in the glass substrate GB2
may be formed near the liquid crystal layer LC in the glass
substrate GB2.
[0086] The configuration can reduce the luminance of a pixel having
a luminance defect, thereby reducing the noticeability of the
luminance defect (leakage of light). This can reduce a display
quality loss caused by a luminance defect and increase the
manufacturing yield of the liquid crystal display LCD. In the
example of the foregoing explanation, the dimmer is provided in
preparation for a luminance defect where a luminance increases. The
dimmer may be provided in preparation for a luminance defect where
a luminance decreases. The dimmer adjusts the transmission of
backlight to suppress the luminance defect.
[0087] A method of manufacturing the liquid crystal display LCD
will be described below.
[0088] The method of manufacturing the liquid crystal display LCD
includes the step of manufacturing the TFT substrate SUB1, the step
of manufacturing the CF substrate SUB2, the step of bonding the TFT
substrate SUB1 and the CF substrate SUB2, the step of injecting a
liquid crystal, the step of testing the lighting of the display
panel DP, and the step of correcting a luminance defect.
[0089] Of these steps, known methods can be used for the step of
manufacturing the TFT substrate SUB1, the step of manufacturing the
CF substrate SUB2, the step of bonding the TFT substrate SUB1 and
the CF substrate SUB2, the step of injecting a liquid crystal, and
the step of testing lighting.
[0090] For example, the step of manufacturing the TFT substrate
SUB1 includes the step of forming the gate lines GL, the data lines
DL, the pixel electrodes PIT, the common electrode CIT, the
insulating films, and the polarizing plate POL1 on the glass
substrate GB1. The pixels P defined in the TFT substrate SUB1 may
include a red pixel for red, a green pixel for green, and a blue
pixel for blue. The step of manufacturing the CF substrate SUB2
includes the step of forming the black matrix BM, the color filter
CF, and the polarizing plate POL2 on the glass substrate GB2.
[0091] The step of testing lighting and the step of correcting a
luminance defect will be discussed below.
[0092] FIG. 15 shows a luminance defect corrector 100. FIG. 13 is a
flowchart showing a method of correcting a luminance defect.
[0093] The luminance defect corrector 100 includes a detector 39
that detects a luminance defect, a drive unit 40 that moves the
irradiation region of an energy beam and the liquid crystal display
LCD relative to each other, and an arithmetic unit 41 that
calculates the position, size, and shape of a luminance defect and
the position, size, and shape of the dimmer formed by irradiation
with an energy beam.
[0094] First, in the step of testing lighting, the detector 39
detects a luminance defect. For example, the detector 39
illuminates the overall display panel DP or each line of the
display panel DP to measure the luminance of each pixel.
Subsequently, the detector 39 detects, as a luminance defect, a
pixel deviating from a predetermined luminance range, for example,
a pixel with a measured luminance larger than a predetermined
threshold value. The detector 39 outputs position information on
pixels detected as luminance defects. A luminance defect may be
visually detected by an operator. When a luminance defect is
detected, the process advances to the step of correcting the
luminance defect.
[0095] The luminance defect corrector 100 includes a high-energy
beam oscillator 101, a slit 102, and a condenser lens 103. In an
example of the present embodiment, the high-energy beam oscillator
101 is a laser having a wavelength of 1552 nm and a pulse width of
800 fs.
[0096] The display device is illuminated (S1) to detect a luminance
defect (S2), and then in the step of correcting the luminance
defect, first, the luminance defect corrector 100 acquires position
information and shape information about pixels having luminance
defects, from the detector 39 (S3).
[0097] Subsequently, the shape of the dimmer 10 to be formed by
irradiation of a high-energy beam is calculated in the arithmetic
unit 41 based on the acquired shape information (S4).
[0098] After that, the drive unit 40 positions the optical system
of the luminance defect corrector 100 based on the acquired
position information. Moreover, the luminance defect corrector 100
adjusts a focus F of the high-energy beam to a desired position in
the glass substrate GB2. The position of the focus F is adjusted
based on, for example, the size of the foreign matter 33, the cause
of a luminance defect, or a measured luminance value. For example,
as shown in FIG. 15, the focus F of the high-energy beam is
adjusted to the vicinity of the foreign matter 33 in the glass
substrate GB2. Subsequently, the luminance defect corrector 100
emits the high-energy beam from the high-energy beam oscillator
101. The high-energy beam emitted from the high-energy beam
oscillator 101 passes through the slit 102, which spatially
transmits the high-energy beam to the formation region of the
dimming region, and then the high-energy beam converges through the
condenser lens 103 to the focus F in the glass substrate GB2. This
forms the dimming region (S5). Subsequently, the drive unit 40
moves the irradiation position of the high-energy beam; meanwhile,
the high-energy beam is continuously emitted. This forms the
multiple dimming regions, leading to the formation of the
dimmer.
[0099] Thus, the dimmer is formed according to the shape and size
of a luminance defect, thereby correcting only a necessary and
sufficient region. As will be described later, after the
correction, a test and a correction are repeated so as to reliably
eliminate an insufficient correction. Hence, a deterioration of
display quality can be further suppressed.
[0100] If the dimmer includes the multiple dimming layers, the
first dimming layer 11 near the foreign matter 33, the cause of a
luminance defect, is preferably formed by a pulse laser having
lower power than the second dimming layer 12 that is farther from
the foreign matter 33 than the first dimming layer 11. When the
power of the pulse laser is reduced, the peak intensity can be
reduced or a wavelength can be increased. Thus, the influence to
the liquid crystal layer LC can be reduced.
[0101] FIG. 14 is a flowchart showing another method of correcting
a luminance defect.
[0102] First, the display device is illuminated (S1) to detect a
luminance defect (S2), and then the luminance defect corrector 100
acquires position information and shape information about pixels
having luminance defects, from the detector 39 (S3). Subsequently,
the shape of the dimmer 10 to be formed by irradiation of a
high-energy beam is calculated in the arithmetic unit 41 based on
the acquired shape information (S4).
[0103] After that, the drive unit 40 positions the optical system
of the luminance defect corrector 100 based on the acquired
position information. Moreover, the luminance defect corrector 100
adjusts the focus F of the high-energy beam to a desired position
in the glass substrate GB2. The position of the focus F is adjusted
based on, for example, the size of the foreign matter 33, the cause
of a luminance defect, or a measured luminance value. For example,
as shown in FIG. 15, the focus F of the high-energy beam is
adjusted to the vicinity of the foreign matter 33 in the glass
substrate GB2. Subsequently, the luminance defect corrector 100
emits the high-energy beam from the high-energy beam oscillator
101. The high-energy beam emitted from the high-energy beam
oscillator 101 passes through the slit 102 and then converges
through the condenser lens 103 to the focus F in the glass
substrate GB2. This forms the dimming region (S5).
[0104] Subsequently, the drive unit 40 moves the irradiation
position of the high-energy beam; meanwhile, the high-energy beam
is continuously emitted. This forms the multiple dimming regions,
leading to the formation of the dimmer 10.
[0105] After the formation of the dimmer 10, a lighting test is
conducted again to confirm the absence of a luminance defect (S6).
Also from the second lighting test, a detected luminance defect is
corrected again. Steps 1 to 5 are repeated until no luminance
defect is detected. From the second test, the dimmer 10 formed in
the correction of a luminance defect may have a different shape or
size from the dimmer 10 formed in the first test.
[0106] FIG. 16 shows another schematic configuration of the
luminance defect corrector 100. The luminance defect corrector 100
includes a high-energy beam oscillator 101, a slit 102, a beam
separator 104, and a condenser lens 103.
[0107] As shown in FIG. 16, the luminance defect corrector 100
emits a high-energy beam from the high-energy beam oscillator 101.
Thus, the high-energy beam emitted from the high-energy beam
oscillator 101 passes through the slit 102 and then is split or
divided into multiple beams by the beam separator 104. The split
high-energy beams are caused to converge through the condenser lens
103 to the focus F in the glass substrate GB2 such that the beams
are superimposed on one another. Subsequently, the high-energy beam
is continuously emitted while the irradiation position of the
high-energy beam is moved. This forms the dimmer 10.
[0108] Thus, a high-energy beam transmitted without contributing to
the formation of the dimmer 10 is considerably dispersed. The
dispersion of the beam lowers the energy density of a high-energy
beam reaching a liquid crystal, thereby reducing damage to the
liquid crystal layer LC. In FIG. 16, the single condenser lens 103
is used. Multiple condenser lenses may be used instead as long as
the focuses of high-energy beams can be superimposed on one another
at a predetermined position of the formation of the dimmer 10. The
multiple condenser lenses are preferably used because the
collection of high-energy beams is improved and the high-energy
beams transmitted through the dimmer 10 are considerably dispersed
so as to reduce damage to the liquid crystal layer LC. The beam
separator 104 may be a beam splitter, a diffractive optical
element, and so on.
[0109] As has been discussed, the dimmer 10 may be formed in the
glass substrate GB2 or each of the glass substrate GB1 and the
glass substrate GB2. If the dimmer 10 is formed in the glass
substrate GB1, a high-energy beam may be emitted to the glass
substrate GB1 from the back side of the display panel DP.
[0110] The high-energy beam oscillator 101 preferably generates a
pulse laser beam of 1 picosecond or less. The high-energy beam
oscillator 101 is preferably capable of oscillating high-energy
beams of multiple wavelengths and selecting the wavelength of the
high-energy beam emitted to form the dimming region.
[0111] In the step of correcting a luminance defect, a glass
material is colored by irradiation of a high-energy beam focusing
on a glass substrate. This does not change the shape of the glass
substrate. For example, the inside or surface of the glass
substrate is not broken so as to change the outside shape. Thus,
the step of correcting a luminance defect can be performed, for
example, in a state in which the polarizing plates POL1 and POL2
are formed in the TFT substrate SUB1 and the CF substrate SUB2,
that is, after the completion of the display panel DP. Since the
dimmer 10 is made of the same material as the glass substrate, the
index of refraction of the dimmer 10 is not changed. Instead of
coloring on the glass material, a phase change of the glass
material may change the transmittance of light.
[0112] In the step of correcting a luminance defect, the intensity
of a high-energy beam to be emitted may be adjusted according to
the color of a pixel corresponding to a part having a luminance
defect. Thus, the dimmer 10 is formed such that the transmittance
of light varies with the color of a pixel corresponding to a part
having a luminance defect. For example, the dimmer 10 covering a
region supposed to have a luminance defect corresponding to a green
pixel may be formed such that it has the transmittance of light
lower than the transmittance of light of the dimmer 10 covering a
region supposed to have a luminance defect corresponding to a pixel
of another color (e.g., a red pixel or a blue pixel).
[0113] The step of manufacturing the TFT substrate SUB1 may include
the step of doping the glass substrate GB1 with a coloring
material. Similarly, the step of manufacturing the CF substrate
SUB2 may include the step of doping the glass substrate GB2 with a
coloring material. In the doping step, for example, a coloring
material may be mixed with a glass material or the surface of the
glass substrate may be coated with a coloring material. The
coloring material may be particles of gold, silver, copper,
aluminum, lead, particles of platinum and so on, or particles of
alloys of these metals. The glass substrate doped with the coloring
material is irradiated with a high-energy beam so as to color the
dimmer 10 according to the coloring material. Thus, a part having a
luminance defect can be changed to a desired color. This can reduce
the noticeability of leakage of light.
[0114] In the foregoing explanation, a luminance defect occurs when
the foreign matter 33 is trapped between the TFT substrate SUB1 and
the CF substrate SUB2. The cause of a luminance defect is not
limited to the foreign matter. For example, light may leak due to a
defect of the thin film transistor TFT or spacers disposed between
the substrates. The method of correcting a luminance defect
according to the present embodiment is also applicable to such
luminance defects.
[0115] Moreover, the foreign matter 33 supposed to cause a
luminance defect is not always trapped between the TFT substrate
SUB1 and the CF substrate SUB2. For example, also in the case of a
foreign matter trapped between the glass substrate GB1 and the
polarizing plate POL1, a luminance defect may occur. In this case,
the dimmer 10 may be formed near the foreign matter 33 in the glass
substrate GB1. Furthermore, also in the case of a foreign matter
trapped between the glass substrate GB2 and the polarizing plate
POL2, a luminance defect may occur. In this case, as shown in FIG.
7, the dimmer 10 may be formed near the foreign matter 33 in the
glass substrate GB2.
[0116] In this way, the foreign matter 33 may be trapped at any
position of the display panel DP. Thus, for example, in the single
display panel DP, the foreign matter 33 that causes a luminance
defect is trapped between the glass substrate GB1 and the
polarizing plate POL1 (first position) and between the glass
substrate GB2 and the polarizing plate POL2 (second position). In
this case, a first dimmer 10 may be formed near the foreign matter
in the glass substrate GB1 so as to correspond to the foreign
matter at the first position, whereas a second dimmer 10 may be
formed near the foreign matter in the glass substrate GB2 so as to
correspond to the foreign matter at the second position. Moreover,
in this case, both of the first dimmer 10 and the second dimmer 10
may be formed near the display surface of the glass substrate GB2
in consideration of working efficiency in the step of correcting a
luminance defect.
[0117] The dimmer is not always formed in the glass substrate and
may be formed on a surface of the glass substrate. For example, the
dimmer may be formed on each of the display surface of the glass
substrate GB1 and the backside surface of the glass substrate GB2.
The dimmer may be formed on each of the backside surface of the
glass substrate GB1 and the display surface of the glass substrate
GB2.
[0118] The embodiments of the present invention were described in
the foregoing explanation. The present invention is not limited to
the embodiments. Needless to say, the technical scope of the
present invention also includes a configuration properly changed by
a person skilled in the art from the embodiments within the scope
of the present invention.
[0119] The present invention is useful particularly for a liquid
crystal display including a display device or an organic
electroluminescent flat panel display and is optimally used for a
display device of a display that requires a high luminance, a high
resolution, and uniform image quality. The present invention can be
widely used for electric equipment and apparatuses having
displays.
LIST OF REFERENCE SIGNS
[0120] LCD liquid crystal display
[0121] DP display panel
[0122] SUB1 TFF substrate
[0123] SUB2 CF substrate
[0124] LC liquid crystal layer
[0125] GB1, GB2 glass substrate
[0126] GSN, PAS, UPAS insulating film
[0127] GL gate line
[0128] DL data line
[0129] SM source electrode
[0130] DM drain electrode
[0131] SEM semiconductor layer
[0132] CIT common electrode
[0133] PIT display electrode
[0134] TFT thin-film transistor
[0135] P pixel
[0136] AF alignment layer
[0137] CF color filter
[0138] BM black matrix
[0139] OC overcoat layer
[0140] POL1, POL2 polarizing plate
[0141] CONT contact hole
[0142] 10 dimmer
[0143] 11 dimming layer
[0144] 12 dimming layer
[0145] 20 dimming region
[0146] 20A dimming region
[0147] 20B dimming region
[0148] 30 data-line driving circuit
[0149] 31 gate-line driving circuit
[0150] 32 opening
[0151] 33 foreign matter
[0152] 34 backlight
[0153] 35, 36 center
[0154] 37 backlight device
[0155] 38 overlapping portion
[0156] 39 detector
[0157] 40 drive unit
[0158] 41 arithmetic unit
[0159] 100 luminance defect corrector
[0160] 101 high-energy beam oscillator
[0161] 102 slit
[0162] 103 condenser lens
[0163] 104 beam separator
[0164] F focus
* * * * *